Smells like sulfur, what is that...

[Daniel 123]

Hi Guys,

Cleaning out the tank these little "pods" looking things were found in one of the overflows, any ideas what they are? Syphoned them out however the water in the overflow smelled like sulfur, this is obviously decay.
I am running a herbie overflow drain, the main drain is about 4.5 inches below the weir on this 30" high tank. Any food particles that fall past the drain end up sitting on the bottom of the overflow, didn't realize how fast this could foul the water, any one experience the same smell or similar?

 

[Big G]

Kinda hard to tell from the pictures, but if they are not moving, they could be pineapple sponges. They bloom in environments with excess nutrients, absorb them and then eventually disappear.

 

[garbled]

A sulfur smell is bad. That's H2S, and is pretty much poisonous to everything. (Although, it does indicate denitrification, but, it's still super bad, because poison)

I would maybe put a tiny pump or something down there to move water around. You do not want that condition in your tank. However.. be *very* *very* careful.. If you push all that H2S laden water into the tank, you could kill alot of stuff. Maybe do a water change and pull from the very bottom, then put the pump in.